Photoelectric conversion device, apparatus, method for forming an optical element array, and method for manufacturing a photoelectric conversion device

Abstract

This technology offers advantages in reducing color mixing. [Solution] A photoelectric conversion device in which a plurality of pixels are arranged on a substrate, each of the plurality of pixels comprises a photoelectric conversion unit and an optical element that functions as a light-collecting element and a color filter, the plurality of pixels include a first pixel and a second pixel arranged adjacent to each other, the optical element of the first pixel and the optical element of the second pixel transmit light of different colors to each other and are in contact with each other, and the contact surface where the optical element of the first pixel and the optical element of the second pixel are in contact is inclined with respect to the direction normal to the surface of the substrate.

Description

Technical Field

[0001] The present invention relates to a photoelectric conversion device, equipment, a method for forming an optical element array, and a method for manufacturing a photoelectric conversion device.

Background Art

[0002] In order to improve the light collection efficiency of a photoelectric conversion element and enhance the sensitivity, it is known to arrange a microlens. Patent Document 1 discloses a solid-state imaging device including pixels in which microlenses are arranged on a color filter corresponding to each photodiode.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration shown in Patent Document 1, if the optical path length between the microlens and the color filter becomes long, the light incident on the microlens of one pixel may enter the color filter of a pixel arranged adjacent to the said pixel, and color mixing may occur. It is required to shorten the optical path length between the light collection element such as a microlens and the color filter.

[0005] The present disclosure aims to provide a technique advantageous for reducing color mixing.

Means for Solving the Problems

[0006] In view of the above problems, an embodiment of the present invention is a photoelectric conversion device in which a plurality of pixels are arranged on a substrate, each of the plurality of pixels comprising a photoelectric conversion unit and an optical element that functions as a light-collecting element and a color filter, the plurality of pixels including a first pixel and a second pixel arranged adjacent to each other, the optical element of the first pixel and the optical element of the second pixel transmit light of different colors to each other and are in contact with each other, and the contact surface where the optical element of the first pixel and the optical element of the second pixel are in contact is inclined with respect to the direction normal to the surface of the substrate. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technology that is advantageous in reducing the amount of color mixing. [Brief explanation of the drawing]

[0008] [Figure 1] A diagram showing an example configuration of the photoelectric conversion device of this embodiment. [Figure 2] A diagram showing an example configuration of a photoelectric conversion device in a comparative example. [Figure 3] Figure 1 shows an example of a manufacturing method for the photoelectric conversion device. [Figure 4] Figure 1 shows an example of a manufacturing method for the photoelectric conversion device. [Figure 5] Figure 1 shows an example of a manufacturing method for the photoelectric conversion device. [Figure 6] Figure 1 shows an example of a manufacturing method for the photoelectric conversion device. [Figure 7] Figure 1 shows an example of a manufacturing method for the photoelectric conversion device. [Figure 8] Figure 1 shows an example of a light-gathering element in a photoelectric conversion device. [Figure 9] Figure 1 shows a modified example of the photoelectric conversion device. [Figure 10] Figure 9 shows an example of a method for manufacturing a photoelectric converter. [Figure 11] Figure 9 shows an example of a method for manufacturing a photoelectric converter. [Figure 12] Figure 9 shows an example of a method for manufacturing a photoelectric converter. [Figure 13] Figure 9 shows an example of a method for manufacturing a photoelectric converter. [Figure 14] Figure 9 shows an example of a method for manufacturing a photoelectric converter. [Figure 15] This figure shows an example of the configuration of an imprint apparatus used when forming the light-gathering element of the photoelectric conversion device of this embodiment. [Figure 16] This figure shows an example of the configuration of a device incorporating the photoelectric conversion device of this embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0010] A photoelectric converter according to an embodiment of the present disclosure will be described with reference to Figures 1 to 16. Figure 1 is a diagram showing an example of the configuration of the photoelectric converter 100 of this embodiment. The photoelectric converter 100 has a plurality of pixels 110 arranged on a substrate 200. Each of the plurality of pixels 110 includes a photoelectric conversion unit 201 arranged on the substrate 200 and an optical element 301 that functions as a light-gathering element and a color filter, arranged on the photoelectric conversion unit 201. A structure 210 is arranged between the substrate 200 and the optical element 301, and a planarization film 220 is arranged between the structure 210 and the optical element 301.

[0011] The substrate 200 may be a semiconductor substrate, for example, made of silicon. The substrate 200 is provided with a photoelectric conversion unit 201, for example, a photodiode. The photoelectric conversion unit 201 converts light incident on the photoelectric conversion unit into an electrical signal (charge). A structure 210, a planarization film 220, an optical element 301, etc., are arranged on the surface 202 of the substrate 200. The surface 202 of the substrate 200 may also be called the main surface.

[0012] The structure 210 can be a passivation film that protects the surface 202 of the substrate 200. A so-called silicon oxide-based dielectric such as silicon oxide, silicon nitride, or silicon oxynitride may be used for the structure 210. Further, for example, a conductor pattern such as a wiring pattern may be arranged in the dielectric that constitutes the structure 210. On the surface 202 of the substrate 200, a transistor or the like connected to the wiring pattern arranged in the structure 210 may be arranged. In the configuration shown in FIG. 1, the photoelectric conversion device 100 has a so-called front-illumination type configuration, but is not limited thereto, and the photoelectric conversion device 100 may have a back-illumination type configuration.

[0013] The planarization film 220 is an underlayer for flattening the surface on which the optical element 301 is formed. It can be said that the optical element 301 is arranged on the planarization film 220 that is an underlayer. The planarization film 220 may be formed of an inorganic material such as silicon oxide or an organic material such as resin. Further, if the surface of the structure 210 has a desired flatness, the optical element 301 may be formed using the structure 210 as an underlayer, and in that case, the planarization film 220 may be omitted (not arranged).

[0014] As shown in FIG. 1, an antireflection film 230 may be arranged so as to cover the optical element 301. A high refractive index material such as tantalum oxide or titanium oxide may be used for the antireflection film 230. The antireflection film 230 may have a single-layer structure of a high refractive index material or a laminated structure of a high refractive index material and a low refractive index material.

[0015] In this embodiment, the optical element 301 functions as a light-gathering element and a color filter. In the configuration shown in Figure 1, the optical element 301 has the shape of a microlens. The optical element 301 may be a resin colored with a pigment or dye. For example, acrylic resin or phenolic resin may be used as the resin. As will be described in detail later, the optical element array 300 comprising a plurality of optical elements 301 is formed by processing a plurality of optical element materials, which are the material for the optical elements 301 and include optical element materials that transmit different colors from each other, using an imprint process. In this embodiment, the optical element 301 may include an optical element 301r that transmits red light, an optical element 301g that transmits green light, and an optical element 301b that transmits blue light. Here, when referring to a specific optical element among the optical elements 301, a subscript is added after the reference number, such as optical element 301 "r", and when any of them may be used, it is simply referred to as optical element "301". The same applies to other components. For example, the optical elements 301r, 301g, and 301b may be arranged in a Bayer array, but are not limited to that, and can be arranged in any appropriate order. Also, the color of light transmitted by the optical elements 301 is not limited to red, green, and blue, and the optical element array 300 may be composed of optical elements 301 that transmit cyan, magenta, and yellow, respectively.

[0016] Figure 2 shows a comparative example of a photoelectric converter 100'. In the photoelectric converter 100', a microlens 401, which functions as a light-gathering element, and a color filter 410 are arranged separately. A planarization film 221 is placed between the microlens 401 and the color filter 410 to suppress the step on the surface of the color filter 410. The planarization film 221 and other elements may increase the optical path length between the microlens 401 and the color filter 410. In that case, for example, light incident on the microlens 401 placed on the color filter 410b may be incident on the color filter 410r or color filter 410g of the adjacent pixel 110', potentially causing color mixing. In contrast, the optical element 301 of this embodiment functions as both a light-gathering element and a color filter, as shown in Figure 1. By integrating the light-gathering element and the color filter, it becomes possible to suppress color mixing.

[0017] Next, a method for manufacturing an optical element array 300 comprising a plurality of optical elements 301 according to this embodiment will be described. Before describing the specific manufacturing method, first, the imprint process used when forming the optical element array 300 will be described. Figure 15 schematically shows an example configuration of an imprint apparatus NIL that can be used to form the optical elements 301. The imprint apparatus NIL is a device that transfers the pattern of a mold M onto a curable composition IM on a substrate S. As the curable composition IM, a composition that hardens when curing energy is applied (sometimes called an uncured resin) is used. As curing energy, electromagnetic waves, heat, etc. As electromagnetic waves, for example, light such as infrared rays, visible light, ultraviolet rays, etc., whose wavelength is selected from the range of 10 nm or more and 1 mm or less. The curable composition IM may be understood as a composition that hardens by irradiation with light or by heating. Among these, a photocurable composition that hardens with light contains at least a polymerizable compound and a photopolymerization initiator, and may optionally contain a non-polymerizable compound or a solvent. The non-polymerizable compound may be at least one selected from the group consisting of sensitizers, hydrogen donors, internal release agents, surfactants, antioxidants, polymer components, and the like. The curable composition IM may be applied to a substrate in a film-like manner by a spin coater or a slit coater. The curable composition IM may also be applied to the substrate by a liquid spray head in the form of droplets, islands formed by multiple droplets being connected, or in a film-like manner. The viscosity (viscosity at 25°C) of the curable composition IM is, for example, 1 mPa·s or more and 100 mPa·s or less.

[0018] The imprint apparatus NIL may include a substrate stage SS including a substrate chuck SC for holding a substrate S, and a substrate drive mechanism SSD for driving the substrate stage SS. The imprint apparatus NIL may also include a mold drive mechanism MD for holding and driving a mold M. The substrate drive mechanism SD and the mold drive mechanism MD constitute a relative drive mechanism that drives at least one of the substrate SD and the mold MD so that the relative position of the substrate S and the mold M is adjusted. The adjustment of the relative position by the relative drive mechanism includes driving for contact of the mold M with the curable composition IM on the substrate S, and for separation of the mold M from the cured product of the curable composition IM. The adjustment of the relative position by the relative drive mechanism also includes alignment of the substrate S (shot area) and the mold M (pattern area PR). The substrate drive mechanism SSD may be configured to drive the substrate S around a plurality of axes (e.g., three axes: X, Y, and θZ; and further, for example, six axes: X, Y, Z, θX, θY, and θZ). The imprint apparatus NIL may include a mold deformation mechanism DM for deforming the two-dimensional shape of the pattern region PR of the mold M. The mold deformation mechanism DM can deform the pattern region PR of the mold M by, for example, applying force to the side of the mold M. The mold drive mechanism MD may be configured to drive the mold M along multiple axes (e.g., three axes: Z-axis, θX-axis, θY-axis, or even six axes: X-axis, Y-axis, Z-axis, θX-axis, θY-axis, θZ-axis). The imprint apparatus NIL may also include a pressure controller CPC that controls the three-dimensional shape of the pattern region PR of the mold M by adjusting the pressure in a sealed space SP formed on the back of the mold M. By adjusting the pressure in the sealed space SP, the pressure controller CPC can deform the pattern region PR of the mold M into a downward convex shape or flatten it.

[0019] The imprint apparatus NIL may include one or more alignment scopes AS for measuring the alignment error between the shot area of ​​the substrate S and the pattern area PR of the mold M. The imprint apparatus NIL may include a curing unit CU for curing the curable composition IM by irradiating it with curing energy through the mold M to form a cured film (cured product). The imprint apparatus NIL may include a dispenser DP for applying or placing the curable composition IM onto the substrate S. The imprint apparatus NIL may include an off-axis scope OAS for detecting the position of alignment marks on the substrate S. The imprint apparatus NIL may include a control unit CNT for controlling each component of the imprint apparatus NIL. The control unit CNT may be an information processing device consisting of, for example, a Programmable Logic Device (PLD) such as a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a computer with a program installed, or a combination of all or some of these.

[0020] The following describes a method for manufacturing an optical element array 300 using an imprint process. First, a substrate 200 is prepared on which multiple optical element materials 310 are arranged, including optical element materials 310r, 301g, and 310b that transmit different colors from each other, as shown in Figure 3. In this embodiment, a photoelectric conversion section 201 is formed on the substrate 200 as described above. In addition, a structure 210 and a planarization film 220 are formed on the surface 202 of the substrate 200. The multiple optical element materials 310 are arranged with the planarization film 220 as an underlayer. However, it is not limited to this. The substrate prepared in this preparation step may be, for example, a substrate on which multiple optical element materials 310 are arranged on a transparent glass or plastic substrate. The transparent substrate does not have to have a photoelectric conversion section. In such cases, the formed optical element array 300 can be used by laminating it with a substrate that has a photoelectric conversion section or a substrate that has a light-emitting element.

[0021] Next, as shown in Figure 3, in the imprint apparatus NIL, a step is performed in which the curable composition 320 (curable composition IM in Figure 15) is placed by the dispenser DP so as to cover the optical element material 310. Also, a mold 330 (mold M in Figure 15) is prepared.

[0022] Once the curable composition 320 is placed, a step is performed to bring the mold 330 into contact with the curable composition 320, as shown in Figure 4. Next, as shown in Figure 5, with the curable composition 320 and the mold 330 in contact, a step is performed to cure the curable composition 320 with a curing unit CU. This forms a cured product 321 of the curable composition 320. After the cured product 321 is formed, a step is performed to separate the mold 330 from the cured product 321, as shown in Figure 6. A process including the steps of placing the curable composition 320 on the optical element material 310, bringing the mold 330 into contact with the curable composition 320, curing the curable composition 320, and separating the mold 330 from the cured product 321 of the curable composition 320 may be called an imprint process. Thus, in this embodiment, a light-gathering element shape is formed on a plurality of optical element materials 310 using an imprint process, with each of the plurality of optical element materials 310 corresponding to a cured product 321 of the curable composition 320.

[0023] After forming a light-gathering element-shaped cured product 321, the light-gathering element shape of the cured product 321 is transferred to each of the optical element materials 310 by etching the cured product 321 and the multiple optical element materials 310. As a result, as shown in Figure 7, multiple optical elements 301 (optical element array 300) that function as light-gathering elements and color filters are formed from the multiple optical element materials 310. In this etching process, if the etching rate of the cured product 321 of the curable composition 320 and the etching rate of the optical element materials 310 are closer in value, the light-gathering element shape of the cured product 321 can be transferred to the optical element materials 310 more accurately. For example, the selectivity ratio of the etching rate of the optical element material 310 to the cured product 321 in this etching process may be 0.7 or more and 1.3 or less. Furthermore, for example, the selectivity ratio of the etching rate of the optical element material 310 to the cured product 321 in this etching process may be 0.9 or more and 1.1 or less. Furthermore, for example, the etching rate of the cured product 321 and the etching rate of the optical element material 310 in this etching process may be equivalent (for example, the selectivity ratio may be approximately 1). For example, the above-described selectivity ratio for etching rates can be achieved by having the optical element material 310 (optical element 301) and the cured product 321 (curable composition 320) contain the same resin material. For example, the optical element material 310 (optical element 301) and the cured product 321 (curable composition 320) may contain acrylic resin. Also, for example, the optical element material 310 (optical element 301) and the cured product 321 (curable composition 320) may contain phenolic resin.

[0024] After the formation of the optical element 301 (optical element array 300), an anti-reflective film 230 may be formed to cover the optical element 301 (optical element array 300), as shown in Figure 1. The optical elements 301 constituting the optical element array 300 may all have the same shape, as shown in Figure 1. Alternatively, the shape of the optical elements 301 may differ depending on the pixel 110, for example. For example, the shapes of the optical elements 301r, 301g, and 301b may differ depending on the color of the transmitted light. For example, at least one of the optical elements 301g and 301b may be formed thinner than the optical element 301r. This can increase sensitivity to blue light, which is less sensitive in the photoelectric conversion unit 201 using a photodiode, and to green light, which the human eye is sensitive to. In addition, in the configuration shown in Figure 1, the center of the microlens-shaped optical element 301 is positioned above the center of the photoelectric conversion unit 201, but the configuration is not limited to this. For example, the center position of the photoelectric conversion unit 201 and the center position of the optical element 301 may be shifted stepwise or continuously as the distance from the center of the substrate 200 increases. The shape of the optical element 301 and its positional relationship with the photoelectric conversion unit 201 may be set appropriately according to the performance required of the optical element 301.

[0025] In this embodiment, the optical element 301 combines the functions of a light-gathering element and a color filter. This shortens (almost eliminates) the optical path length between the light-gathering element and the color filter, thereby suppressing color mixing between pixels 110. Furthermore, as described above, by using an imprint process, an optical element array 300 comprising multiple optical elements 301 that function as light-gathering elements and color filters can be formed. This may allow for easier formation of the optical element array 300 than using a photolithography process (including exposure and development processes) that uses precise halftone masks.

[0026] Figures 3(a) to 3(c) show examples of optical elements having a light-gathering function. Figure 3(a) shows an example in which a microlens is used as the optical element 301 described above. The microlens may be a spherical lens or an aspherical lens. However, the light-gathering element is not limited to a microlens. As shown in Figure 3(b), a Fresnel lens may be used as the optical element 302. A Fresnel lens can be made shorter in height compared to, for example, a microlens with the same power. This can facilitate the formation of a light-gathering element-shaped cured product 321 from the curable composition 320 in the imprint process. Also, as shown in Figure 3(c), a binary optics may be used as the optical element 303. For example, the binary optics may be formed with a rectangular cross-section of the same height, as shown in Figure 3(c). This can further facilitate the formation of a light-gathering element-shaped cured product 321 from the curable composition 320 in the imprint process. However, it is not limited to this, and the cross-sectional shape of the binary optics may be stepped.

[0027] Furthermore, in the configurations shown in Figures 3(a) to 3(c), the ends of the optical elements 301 to 303 between adjacent pixels 110 are arranged to be in contact with each other. However, this is not the only arrangement; the optical elements 301 to 303 between adjacent pixels 110 may be arranged, for example, at a predetermined interval.

[0028] Next, a modified version of the photoelectric converter 100 shown in Figure 1 will be described using Figure 9. In the photoelectric converter 100 shown in Figure 9, the shape of the optical elements 301 arranged in the optical element array 300 differs from the configuration shown in Figure 1. Other configurations may be the same as those described above, so the following explanation will focus on the differences, and explanations of configurations that may be the same will be omitted as appropriate.

[0029] In the configuration shown in Figure 1, the optical path length through the optical element 301 changes significantly between light incident on the center of the optical element 301 and light incident on its edge. Therefore, for example, light passing through the edge of optical element 301b may transmit a large amount of both red and green components. As a result, the quality of information (image) obtained by the photoelectric converter 100 may decrease. Therefore, in the configuration shown in Figure 9, the optical elements 304 of adjacent pixels 110 are in contact with each other. This makes it possible for optical element 304 to reduce the difference in optical path length between light incident on the center of the optical element 304 and light incident on its edge compared to optical element 301. This can suppress the deterioration of the quality of information (image) obtained by the photoelectric converter 100. For example, the planarization film 220, which is the underlying layer, does not need to be exposed between adjacent pixels 110. Furthermore, for example, in a photoelectric converter 100, the planarization film 220, which is the underlying layer, does not need to be exposed between the optical element 304 of one pixel 110 and the optical elements 304 of two or more pixels 110 that are adjacent to that pixel 110. For example, in an optical element array 300, the planarization film 220, which is the underlying layer, does not need to be exposed. This can reduce the difference in optical path length corresponding to the portion of light incident on each optical element 304.

[0030] For example, the optical element 304r of adjacent pixels 110r and the optical element 304g of adjacent pixels 110g transmit light of different colors to each other and are in contact with each other. Similarly, the optical element 304b of adjacent pixels 110b and the optical element 304g of adjacent pixels 110g transmit light of different colors and are in contact with each other. For example, in the case of a Bayer array, a pixel 110g equipped with an optical element 304g that transmits green light is arranged to be adjacent to a pixel 110r equipped with an optical element 304r that transmits red light and a pixel 110b equipped with an optical element 304b that transmits blue light. Also, in the configuration shown in Figure 9, the contact surface 311rg where the optical element 304g of pixel 110g and the optical element 304r of pixel 110r are inclined with respect to the direction normal to the surface 202 of the substrate 200. Similarly, the contact surface 311gb where the optical element 304g of pixel 110g and the optical element 304b of pixel 110b are inclined with respect to the normal direction of the surface 202 of the substrate 200. Likewise, the contact surface 311rb where the optical element 304r of pixel 110r and the optical element 304b of pixel 110b are inclined with respect to the normal direction of the surface 202 of the substrate 200. In the configuration shown in Figure 9, the contact surface 311rg is configured such that a portion of the optical element 304g of pixel 110g is positioned between the optical element 304r of pixel 110r and the surface 202 of the substrate 200. Furthermore, the contact surface 311gb is configured such that a portion of the optical element 304g of pixel 110g is positioned between the optical element 304b of pixel 110b and the surface 202 of the substrate 200. Furthermore, the contact surface 311rb is configured such that a portion of the optical element 304b of pixel 110b is positioned between the optical element 304r of pixel 110r and the surface 202 of the substrate 200. The manufacturing method of the optical element array 300 (photoelectric converter 100) equipped with the optical element 304 will be described below with reference to Figures 10 to 14.

[0031] First, a substrate 200 is prepared on which multiple optical element materials 310 are arranged, including optical element materials 310r, 301g, and 310b that transmit different colors from each other, as shown in Figure 10. The preparation process for forming these multiple optical element materials 310 will be explained in more detail. First, a material film of optical element material 310g is formed using, for example, a coating method. Examples of coating methods include spin coating, dipping, and spraying. Next, the material film of optical element material 310g is patterned using a photolithography process. The material film of optical element material 310g is exposed with a suitable photomask. The material film of optical element material 310g may be a negative-type photosensitive resin or a positive-type photosensitive resin. The exposed material film of optical element material 310g is developed, and if the material film of optical element material 310g is a negative-type photosensitive resin, the exposed portion remains after development. The portion remaining after this patterning becomes the optical element material 310g. In this case, the optical element material 310g may be formed in a tapered shape, as shown in Figure 10, where the side walls do not rise perpendicularly (normal to the surface 202 of the substrate 200) from the planarization film 220 which is the underlying layer, but rather become smaller as they move away from the surface 202 of the substrate 200. This makes it easier for the material film of the optical element material 310g, which is then deposited using a coating method or the like, to penetrate between the formed optical element material 310g compared to when the side walls of the optical element material 310g rise perpendicularly, which can lead to an improvement in manufacturing yield. The tapered shape of the optical element material 310g may be controlled by the amount of defocus in the exposure step of the photolithography process when forming the optical element material 310g from the material film of the optical element material 310g.

[0032] Next, a material film of the optical element material 310b is formed using a coating method or the like. Examples of coating methods include spin coating, dipping, and spraying. Then, the material film of the optical element material 310b is patterned using a photolithography process. The material film of the optical element material 310b is exposed with a suitable photomask. The material film of the optical element material 310b may be a negative-type photosensitive resin or a positive-type photosensitive resin. The exposed material film of the optical element material 310b is developed, and if the material film of the optical element material 310b is a negative-type photosensitive resin, the exposed portion remains after development. The portion remaining after this patterning becomes the optical element material 310b. The contact surface 311gb of the optical element material 310b that contacts the optical element material 310g is formed such that a portion of the optical element material 310g is positioned between the optical element material 310b and the surface 202 of the substrate 200, due to the aforementioned shape of the optical element material 310g. In other words, the contact surface 311gb between the optical element material 310g and the optical element material 310b is inclined with respect to the direction normal to the surface 202 of the substrate 200 on which the optical element materials 310g and 310b are arranged. As a result, the contact surface 311gb is ultimately configured such that a portion of the optical element 304g of the pixel 110g is positioned between the optical element 304b of the pixel 110b and the surface 202 of the substrate 200, as shown in Figure 9. Furthermore, the portion of the optical element material 310b that does not contact the optical element material 310g may be formed into a tapered shape that becomes smaller as it moves away from the surface 202 of the substrate 200, as shown in Figure 10. As a result, the material film of the optical element material 310, which is then formed using a coating method or the like, can more easily penetrate between the formed optical element materials 310g and 310b than if the side walls of the optical element materials 310g and 310b were to stand vertically. The shape of the optical element material 310b may be controlled by the amount of defocus in the exposure step of the photolithography process when forming the optical element material 310b from the material film of the optical element material 310b. Also, as shown in Figure 10, the edges of the optical element material 310b may be formed to overlap the edges of the optical element material 310g. In other words, the film thickness of the optical element material 310b may be thicker than the film thickness of the optical element material 310g.

[0033] After the formation of the optical element material 310b, a material film of the optical element material 310r is formed using a coating method or the like. Examples of coating methods include spin coating, dipping, and spraying. Next, the material film of the optical element material 310r is patterned using a photolithography process. The material film of the optical element material 310r is exposed using a suitable photomask. The material film of the optical element material 310r may be a negative-type photosensitive resin or a positive-type photosensitive resin. The exposed material film of the optical element material 310r is developed, and if the material film of the optical element material 310r is a negative-type photosensitive resin, the exposed portion remains after development. This remaining portion, after patterning, becomes the optical element material 310r. The contact surface 311rg of the optical element material 310r that is in contact with the optical element material 310r is formed such that a portion of the optical element material 310g is positioned between the optical element material 310r and the surface 202 of the substrate 200, due to the aforementioned shape of the optical element material 310g. In other words, the contact surface 311rg between the optical element material 310r and the optical element material 310g is tilted with respect to the direction normal to the surface 202 of the substrate 200 on which the optical element materials 310r and 310g are arranged. As a result, the contact surface 311rg is ultimately configured such that a portion of the optical element 304g of the pixel 110g is positioned between the optical element 304r of the pixel 110r and the surface 202 of the substrate 200, as shown in Figure 9. Furthermore, the contact surface 311rb of the optical element material 310r that contacts the optical element material 310b is formed such that a portion of the optical element material 310b is positioned between the optical element material 310r and the surface 202 of the substrate 200, due to the aforementioned shape of the optical element material 310b. In other words, the contact surface 311rb between the optical element material 310r and the optical element material 310b is inclined with respect to the direction normal to the surface 202 of the substrate 200 on which the optical element materials 310r and 310b are arranged. As a result, the contact surface 311rb is ultimately configured such that a portion of the optical element 304b of the pixel 110b is positioned between the optical element 304r of the pixel 110r and the surface 202 of the substrate 200, as shown in Figure 9.Since the shape of the optical element material 310r is formed last among the three types of optical element materials 310r, 310g, and 310b, it may be formed in a tapered shape that increases as it moves away from the surface 202 of the substrate 200, as shown in Figure 10. Also, as shown in Figure 10, the edges of the optical element material 310r may be formed to overlap the edges of the optical element materials 310g and 310b. In other words, the film thickness of the optical element material 310r may be thicker than the film thickness of the optical element materials 310g and 310b.

[0034] In this embodiment, a green light-transmitting optical element material 310g is formed first, followed by a blue light-transmitting optical element material 310b, and finally a red light-transmitting optical element material 310r. As a result, the inclination of the contact surface 311 with respect to the normal direction of the surface 202 of the substrate 200 is as described above. However, this is not the only way; the optical element materials 310 that transmit each color can be formed in an appropriate order. The direction of the inclination of the contact surface 311 can be determined according to the order in which they are formed. Furthermore, although this explanation uses the example of using three types of optical element materials 310r, 310g, and 310b, two or more types of optical element materials 310 may be used. In that case as well, the direction of the inclination of the contact surface 311 can be determined according to the order in which the optical element materials 310 are formed.

[0035] In this embodiment as well, the substrate 200 on which the optical element material 310 is arranged has a photoelectric conversion section 201 formed thereon, as described above. In addition, the structure 210 and the planarization film 220 are formed on the surface 202 of the substrate 200. However, the embodiment is not limited to this, and the substrate prepared in this preparation step may be, for example, a substrate on which a plurality of optical element materials 310 are arranged. The transparent substrate does not have to have a photoelectric conversion section. In such a case, the formed optical element array 300 can be used in a laminated state with a substrate having a photoelectric conversion section or a substrate having a light-emitting element.

[0036] Next, the imprint process is carried out in the same manner as described above. First, as shown in Figure 10, in the imprint apparatus NIL, a step is performed in which the curable composition 320 (curable composition IM in Figure 15) is placed by the dispenser DP so as to cover the optical element material 310. Also, the mold 330 (mold M in Figure 15) is prepared.

[0037] Once the curable composition 320 is placed, as shown in Figure 11, the mold 330 is aligned to a predetermined position and brought into contact with the curable composition 320. Next, as shown in Figure 12, with the curable composition 320 and the mold 330 in contact, the curable composition 320 is cured by the curing unit CU. This forms a cured product 321 of the curable composition 320. After the cured product 321 is formed, as shown in Figure 13, the mold 330 is separated from the cured product 321. In this way, in this embodiment, using an imprint process, a light-gathering element shape consisting of a cured product 321 of the curable composition 320 is formed on a plurality of optical element materials 310, corresponding to each of the plurality of optical element materials 310.

[0038] After forming a light-gathering element-shaped cured product 321, the light-gathering element shape of the cured product 321 is transferred to each of the optical element materials 310 by etching the cured product 321 and the multiple optical element materials 310. As a result, as shown in Figure 14, multiple optical elements 304 (optical element array 300) that function as light-gathering elements and color filters are formed from the multiple optical element materials 310. In this etching process, if the etching rate of the cured product 321 of the curable composition 320 and the etching rate of the optical element materials 310 are closer to each other, the light-gathering element shape of the cured product 321 can be transferred to the optical element materials 310 more accurately. For example, as shown in Figures 10 to 13, there may be cases where the thicknesses of the optical element materials 310r, 310g, and 310b are different. Even in such cases, by making the etching rates of the cured product 321 of the curable composition 320 and the optical element material 310 close, the surface shape of the cured product 321 can be more accurately transferred to the optical element material 310.

[0039] For example, the selectivity ratio of the etching rate of the optical element material 310 to the cured product 321 in this etching process may be 0.7 or more and 1.3 or less. Furthermore, for example, the selectivity ratio of the etching rate of the optical element material 310 to the cured product 321 in this etching process may be 0.9 or more and 1.1 or less. Also, for example, the etching rate of the cured product 321 and the etching rate of the optical element material 310 in this etching process may be equivalent (for example, the selectivity ratio is approximately 1). For example, the above-described selectivity ratio of etching rates can be achieved by having the optical element material 310 (optical element 304) and the cured product 321 (curable composition 320) contain the same resin material. For example, the optical element material 310 (optical element 304) and the cured product 321 (curable composition 320) may contain acrylic resin. Also, for example, the optical element material 310 (optical element 304) and the cured product 321 (curable composition 320) may contain phenolic resin.

[0040] After the formation of the optical element 304 (optical element array 300), an anti-reflective film 230 may be formed to cover the optical element 304 (optical element array 300), as shown in Figure 9. The optical elements 304 constituting the optical element array 300 may all have the same shape, as shown in Figure 9. Alternatively, the shape of the optical elements 301 may differ depending on the pixel 110, for example. For example, the shapes of the optical elements 304r, 304g, and 304b may differ depending on the color of the transmitted light. For example, at least one of the optical elements 304g and 304b may be formed thinner than the optical element 304r. This can increase sensitivity to blue light, which is less sensitive in the photoelectric conversion unit 201 using a photodiode, and to green light, which the human eye is sensitive to. In addition, in the configuration shown in Figure 9, the center of the microlens-shaped optical element 304 is positioned above the center of the photoelectric conversion unit 201, but it is not limited to this configuration. For example, the center position of the photoelectric conversion unit 201 and the center position of the optical element 304 may be shifted stepwise or continuously as the distance from the center of the substrate 200 increases. The shape of the optical element 304 and its positional relationship with the photoelectric conversion unit 201 may be set appropriately according to the performance required of the optical element 304.

[0041] In this embodiment as well, the optical element 304 combines the functions of a light-gathering element and a color filter, similar to the optical element 301 described above. This shortens (almost eliminates) the optical path length between the light-gathering element and the color filter, thereby suppressing color mixing between pixels 110. Furthermore, as described above, by using an imprint process, an optical element array 300 comprising multiple optical elements 301 that function as light-gathering elements and color filters can be formed. This may allow for easier formation of the optical element array 300 than using a photolithography process that uses precise halftone masks, etc.

[0042] Furthermore, in the configuration shown in Figure 9, a microlens is used as the optical element 304, but as shown in Figures 3(b) and 3(c), a Fresnel lens or binary optics may also be used as the optical element 304. In that case, the optical elements 304 of adjacent pixels 110 may be arranged so that the underlying layer (planarization film 220 in the configuration of Figure 9) is not exposed between them.

[0043] Here, an application example of the photoelectric converter 100 of this embodiment will be described using Figure 16. Figure 16 is a schematic diagram of equipment 9191 equipped with the photoelectric converter 100. As shown in Figure 16, the photoelectric converter 100 is housed in a package 920. The package 920 may include a base on which the photoelectric converter 100 is fixed, and a lid made of glass or the like that faces the photoelectric converter 100. The package 920 may further include bonding members such as bonding wires or bumps that connect terminals provided on the base to pads provided on the photoelectric converter 100.

[0044] The device 9191 may include at least one of the following: an optical device 940, a control device 950, a processing device 960, a display device 970, a storage device 980, and a mechanical device 990. The optical device 940 is configured to form an image on the pixel area PXR where the pixels 110 of the photoelectric converter 100 are located, and is, for example, a lens, shutter, or mirror. The control device 950 controls the photoelectric converter 100. The control device 950 is, for example, a semiconductor device such as an Application Specific Integrated Circuit (ASIC).

[0045] The processing unit 960 processes the signal output from the photoelectric converter 100. The processing unit 960 is a semiconductor device such as a Central Processing Unit (CPU) or ASIC for configuring an analog front end (AFE) or a digital front end (DFE). The display device 970 is an EL display device or liquid crystal display device that displays the information (image) obtained from the photoelectric converter 100. The storage device 980 is a magnetic device or semiconductor device that stores the information (image) obtained from the photoelectric converter 100. The storage device 980 is a volatile memory such as SRAM or DRAM, or a non-volatile memory such as flash memory or a hard disk drive.

[0046] The mechanical device 990 has movable parts or propulsion parts such as motors or engines. The device 9191 displays the signals output from the photoelectric converter 100 on the display device 970 or transmits them to the outside using a communication device (not shown) provided in the device 9191. For this purpose, the device 9191 may further include a storage device 980 and a processing device 960, separate from the memory circuits and arithmetic circuits of the photoelectric converter 100. The mechanical device 990 may be controlled based on the signals output from the photoelectric converter 100.

[0047] Furthermore, the device 9191 is suitable for electronic devices such as information terminals with shooting capabilities (e.g., smartphones and wearable devices) and cameras (e.g., interchangeable lens cameras, compact cameras, video cameras, and surveillance cameras). In a camera, the mechanical device 990 can drive components of the optical device 940 for zooming, focusing, and shutter operation. Alternatively, the mechanical device 990 in a camera can move the photoelectric converter 100 for vibration damping.

[0048] Furthermore, the device 9191 can also be applied to on-board cameras mounted on transportation equipment such as vehicles, ships, airplanes, and industrial robots. The mechanical device 990 in transportation equipment can be used as a mobile device. As transportation equipment, the device 9191 is suitable for transporting the photoelectric converter 100 or for assisting and / or automating driving (operation) through its imaging function. The processing device 960 for assisting and / or automating driving (operation) can perform processing to operate the mechanical device 990 as a mobile device based on information obtained from the photoelectric converter 100. The device 9191 incorporating the photoelectric converter 100 can be applied not only to transportation equipment but also to a wide range of equipment that utilizes object recognition, such as intelligent transportation systems (ITS). Alternatively, the device 9191 may be medical equipment such as endoscopes, measuring instruments such as distance sensors, analytical instruments such as electron microscopes, or office equipment such as photocopiers.

[0049] This disclosure includes the following photoelectric conversion devices, equipment, methods for forming optical element arrays, and methods for manufacturing photoelectric conversion devices.

[0050] (Item 1) A photoelectric conversion device in which multiple pixels are arranged on a substrate, Each of the aforementioned plurality of pixels comprises a photoelectric conversion unit and an optical element that functions as a light-collecting element and a color filter, The plurality of pixels include a first pixel and a second pixel arranged to be adjacent to each other, The optical element of the first pixel and the optical element of the second pixel transmit light of different colors to each other and are in contact with each other. A photoelectric conversion device characterized in that the contact surface between the optical element of the first pixel and the optical element of the second pixel is inclined with respect to the direction normal to the surface of the substrate.

[0051] (Item 2) Each of the aforementioned plurality of pixels has an optical element, which is arranged on a base layer. The photoelectric conversion device according to item 1, characterized in that the underlying layer is not exposed between the optical element of the first pixel and the optical element of the second pixel.

[0052] (Item 3) The photoelectric conversion device according to item 2, characterized in that the underlying layer is not exposed between the optical element of the first pixel and the optical elements of two or more pixels, including the second pixel which is arranged adjacent to the first pixel among the plurality of pixels.

[0053] (Item 4) The plurality of pixels further include a third pixel arranged adjacent to the first pixel, The optical element of the third pixel transmits light of a different color than the optical element of the first pixel and the optical element of the second pixel. The optical element of the first pixel and the optical element of the third pixel are in contact with each other. A photoelectric conversion device according to any one of items 1 to 3, characterized in that the contact surface is the first contact surface, and the second contact surface in which the optical element of the first pixel and the optical element of the third pixel are in contact is inclined with respect to the normal direction.

[0054] (Item 5) The first contact surface is configured such that a portion of the optical element of the first pixel is positioned between the optical element of the second pixel and the surface. The photoelectric conversion device according to item 4, characterized in that the second contact surface is configured such that a portion of the optical element of the first pixel is disposed between the optical element of the third pixel and the surface.

[0055] (Item 6) The photoelectric conversion device according to any one of items 1 to 5, characterized in that the optical element provided by each of the plurality of pixels is a microlens.

[0056] (Item 7) The photoelectric conversion device according to any one of items 1 to 5, characterized in that the optical element provided by each of the plurality of pixels is a Fresnel lens.

[0057] (Item 8) The photoelectric conversion device according to any one of items 1 to 5, characterized in that the optical element provided by each of the plurality of pixels is a binary optics.

[0058] (Item 9) A photoelectric converter described in any one of items 1 through 8, A processing device that processes the signal output from the aforementioned photoelectric converter, A device characterized by being equipped with the following features.

[0059] (Item 10) A method for forming an optical element array, A preparation step of preparing a substrate on which multiple optical element materials, including optical element materials that transmit different colors from each other, are arranged, A step of forming a light-gathering element shape on the plurality of optical element materials using an imprint process, with each of the plurality of optical element materials corresponding to a cured product of a curable composition, A step of transferring the shape of the light-gathering element to each of the multiple optical element materials by etching the cured product and the multiple optical element materials, thereby forming multiple optical elements that each function as a light-gathering element and a color filter, A method for forming an optical element array, characterized by including the following:

[0060] (Item 11) The method for forming an optical element array according to item 10, characterized in that the selectivity ratio of the etching rates of the plurality of optical element materials to the cured product in the etching step is 0.7 or more and 1.3 or less.

[0061] (Item 12) A method for forming an optical element array according to item 10 or 11, characterized in that the plurality of optical element materials and the cured product contain the same resin material.

[0062] (Item 13) A method for forming an optical element array according to any one of items 10 to 12, characterized in that each of the plurality of optical elements is a microlens.

[0063] (Item 14) A method for forming an optical element array according to any one of items 10 to 12, characterized in that each of the plurality of optical elements is a Fresnel lens.

[0064] (Item 15) A method for forming an optical element array according to any one of items 10 to 12, characterized in that each of the plurality of optical elements is a binary optics.

[0065] (Item 16) In the preparation step, the plurality of optical element materials include a first optical element material and a second optical element material arranged adjacent to each other. The first optical element material and the second optical element material transmit light of different colors to each other and are in contact with each other. A method for forming an optical element array according to any one of items 10 to 15, characterized in that the contact surface where the first optical element material and the second optical element material are in contact is inclined with respect to the direction normal to the surface of the substrate on which the plurality of optical materials are arranged.

[0066] (Item 17) The preparation step includes forming the first optical element material using a photolithography process, and then forming the second optical element material. The method for forming an optical element array according to item 16, characterized in that the inclination of the contact surface is controlled by the amount of defocusing when forming the first optical element material.

[0067] (Item 18) A method for manufacturing a photoelectric conversion device comprising multiple photoelectric conversion units and multiple color filters, A manufacturing method characterized in that the plurality of color filters are the plurality of optical elements formed using the method for forming an optical element array described in any one of items 10 to 15.

[0068] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0069] 100: Photoelectric converter, 110: Pixel, 200: Substrate, 201: Photoelectric converter unit, 300: Optical element array, 301: Optical element, 310: Optical element material, 311: Contact surface, 320: Curable composition, 321: Cured product

Claims

1. A photoelectric conversion device in which multiple pixels are arranged on a substrate, Each of the aforementioned plurality of pixels comprises a photoelectric conversion unit and an optical element that functions as a light-collecting element and a color filter, The plurality of pixels include a first pixel and a second pixel arranged to be adjacent to each other. The optical element of the first pixel and the optical element of the second pixel transmit light of different colors to each other and are in contact with each other. A photoelectric conversion device characterized in that the contact surface between the optical element of the first pixel and the optical element of the second pixel is inclined with respect to the direction normal to the surface of the substrate.

2. Each of the aforementioned plurality of pixels is provided with an optical element, which is arranged on a base layer. The photoelectric conversion device according to claim 1, characterized in that the underlying layer is not exposed between the optical element of the first pixel and the optical element of the second pixel.

3. The photoelectric conversion device according to claim 2, characterized in that the underlying layer is not exposed between the optical element of the first pixel and the optical elements of two or more pixels, including the second pixel which is arranged adjacent to the first pixel among the plurality of pixels.

4. The plurality of pixels further include a third pixel arranged adjacent to the first pixel, The optical element of the third pixel transmits light of a different color than the optical element of the first pixel and the optical element of the second pixel. The optical element of the first pixel and the optical element of the third pixel are in contact with each other. The photoelectric conversion device according to claim 1, characterized in that the contact surface is the first contact surface, and the second contact surface in which the optical element of the first pixel and the optical element of the third pixel are in contact is inclined with respect to the normal direction.

5. The first contact surface is configured such that a portion of the optical element of the first pixel is positioned between the optical element of the second pixel and the surface. The photoelectric conversion device according to claim 4, characterized in that the second contact surface is configured such that a part of the optical element of the first pixel is disposed between the optical element of the third pixel and the surface.

6. The photoelectric conversion device according to claim 1, characterized in that the optical elements provided by each of the plurality of pixels are microlenses.

7. The photoelectric conversion device according to claim 1, characterized in that the optical element provided by each of the plurality of pixels is a Fresnel lens.

8. The photoelectric conversion device according to claim 1, characterized in that the optical elements provided by each of the plurality of pixels are binary optics.

9. A photoelectric conversion device according to any one of claims 1 to 8, A processing device that processes the signal output from the aforementioned photoelectric converter, A device characterized by being equipped with the following features.

10. A method for forming an optical element array, A preparation step of preparing a substrate on which multiple optical element materials, including optical element materials that transmit different colors from each other, are arranged, A step of forming a light-gathering element shape on the plurality of optical element materials using an imprint process, with each of the plurality of optical element materials corresponding to a cured product of a curable composition, An etching step is performed to transfer the shape of the light-gathering element to each of the multiple optical element materials by etching the cured product and the multiple optical element materials, thereby forming multiple optical elements that each function as a light-gathering element and a color filter. A method for forming an optical element array, characterized by including the following:

11. The method for forming an optical element array according to claim 10, characterized in that the selectivity ratio of the etching rates of the plurality of optical element materials to the cured product in the etching step is 0.7 or more and 1.3 or less.

12. The method for forming an optical element array according to claim 10, characterized in that the plurality of optical element materials and the cured product contain the same resin material.

13. The method for forming an optical element array according to claim 10, characterized in that each of the plurality of optical elements is a microlens.

14. The method for forming an optical element array according to claim 10, characterized in that each of the plurality of optical elements is a Fresnel lens.

15. The method for forming an optical element array according to claim 10, characterized in that each of the plurality of optical elements is a binary optics.

16. In the preparation step, the plurality of optical element materials include a first optical element material and a second optical element material arranged adjacent to each other. The first optical element material and the second optical element material transmit light of different colors to each other and are in contact with each other. The method for forming an optical element array according to claim 10, characterized in that the contact surface between the first optical element material and the second optical element material is inclined with respect to the direction normal to the surface of the substrate on which the plurality of optical element materials are arranged.

17. The preparation step includes forming the first optical element material using a photolithography process, and then forming the second optical element material. The method for forming an optical element array according to claim 16, characterized in that the inclination of the contact surface is controlled by the amount of defocusing when forming the first optical element material.

18. A method for manufacturing a photoelectric conversion device comprising multiple photoelectric conversion units and multiple color filters, A manufacturing method characterized in that the plurality of color filters are the plurality of optical elements formed using the method for forming an optical element array described in any one of claims 10 to 17.

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